Surface Landmarks Research Articles

"Direct DICOM Slice Landmarking" A Novel Research Technique to Quantify Skeletal Changes in Orthognathic Surgery.

The limitations of the current methods of quantifying the surgical movements of facial bones inspired this study. The aim of this study was the assessment of the accuracy and reproducibility of directly landmarking of 3D DICOM images (Digital Imaging and Communications in Medicine) to quantify the changes in the jaw bones following surgery. The study was carried out on plastic skull to simulate the surgical movements of the jaw bones. Cone beam CT scans were taken at 3mm, 6mm, and 9mm maxillary advancement; together with a 2mm, 4mm, 6mm and 8mm “down graft” which in total generated 12 different positions of the maxilla for the analysis. The movements of the maxilla were calculated using two methods, the standard approach where distances between surface landmarks on the jaw bones were measured and the novel approach where measurements were taken directly from the internal structures of the corresponding 3D DICOME slices. A one sample t-test showed that there was no statistically significant difference between the two methods of measurements for the y and z directions, however, the x direction showed a significant difference. The mean difference between the two absolute measurements were 0.34±0.20mm, 0.22±0.16mm, 0.18±0.13mm in the y, z and x directions respectively. In conclusion, the direct landmarking of 3D DICOM image slices is a reliable, reproducible and informative method for assessment of the 3D skeletal changes. The method has a clear clinical application which includes the analysis of the jaw movements “orthognathic surgery” for the correction of facial deformities.

Paediatric vascular access

### Key points Obtaining reliable vascular access in small children is frequently made challenging by anatomical factors—in particular, small, mobile veins and an excess of subcutaneous fat which make visualization and palpation of veins difficult. Paediatric patients are often less co-operative, and the potential for psychological trauma, especially with repeated procedures in the conscious patient, further complicates matters. Short-term vascular access is frequently required in hospitalized children for the delivery of i.v. fluids, medication, and blood product administration. Longer-term vascular access devices are required for repeated medication delivery (e.g. enzyme replacement therapy in inherited metabolic diseases), chemotherapy, immunotherapy, total parenteral nutrition, and extracorporeal procedures such as plasmapheresis and haemodialysis. In addition, vascular access devices may be needed for repeated blood sampling and invasive haemodynamic monitoring. The choice of vascular access device depends upon the condition and preference of the patient or parent/guardian, the likely duration and frequency of treatment, and the properties of the infusate. Infusates with vesicant properties (drugs with the potential to cause blistering with tissue injury, e.g. calcium solutions and amphotericin B), hypertonic solutions, and those with pH 9 will necessitate central venous access. Vasopressors and inotropes are preferentially administered centrally as they require reliable access and extravasation may cause tissue necrosis. It is important to try to predict future needs for vascular access as poor prospective management …

Automatic segmentation of nerve structures in ultrasound images using Graph Cuts and Gaussian processes.

Peripheral Nerve Blocking (PNB), is a procedure used for performing regional anesthesia, that comprises the administration of anesthetic in the proximity of a nerve. Several techniques have been used with the purpose of locating nerve structures when the PNB procedure is performed: anatomical surface landmarks, elicitation of paresthesia, nerve stimulation and ultrasound imaging. Among those, ultrasound imaging has gained great attention because it is not invasive and offers an accurate location of the nerve and the structures around it. However, the segmentation of nerve structures in ultrasound images is a difficult task for the specialist, since such images are affected by echo perturbations and speckle noise. The development of systems for the automatic segmentation of nerve structures can aid the specialist for locating nerve structures accurately. In this paper we present a methodology for the automatic segmentation of nerve structures in ultrasound images. An initial step is carried out using Graph Cut segmentation in order to generate regions of interest; we then use machine learning techniques with the aim of segmenting the nerve structure; here, a specific non-linear Wavelet transform is used for the feature extraction stage, and Gaussian processes for the classification step. The methodology performance is measured in terms of accuracy and the dice coefficient. Results show that the implemented methodology can be used for automatically segmenting nerve structures.

Using an Individual Procedure Score Before and After the Advanced Surgical Skills Exposure for Trauma Course Training to Benchmark a Hemorrhage-Control Performance Metric

Test with an individual procedure score (IPS) to assess whether an unpreserved cadaver trauma training course, including upper and lower limb vascular exposure, improves correct identification of surgical landmarks, underlying anatomy, and shortens time to vascular control. Prospective study of performance of 3 vascular exposure and control procedures (axillary, brachial, and femoral arteries) using IPS metrics by 2 colocated and trained evaluators before and after training with the Advanced Surgical Skills Exposure for Trauma (ASSET) course. IPS, including identification of anatomical landmarks, incisions, underlying structures, and time to completion of each procedure was compared before and after training using repeated measurement models. Audio-video instrumented cadaver laboratory at University of Maryland School of Medicine. A total of 41 second to sixth year surgical residents from surgical programs throughout Mid-Atlantic States who had not previously taken the ASSET course were enrolled, 40 completed the pre- and post-ASSET performance evaluations. After ASSET training, all components of IPS increased and time shortened for each of the 3 artery exposures. Procedure steps performed correctly increased 57%, anatomical knowledge increased 43% and skin incision to passage of a vessel loop twice around the correct vessel decreased by a mean of 2.5 minutes. An overall vascular trauma readiness index, a comprehensive IPS score for 3 procedures increased 28% with ASSET Training. Improved knowledge of surface landmarks and underlying anatomy is associated with increased IPS, faster procedures, more accurate incision placement, and successful vascular control. Structural recognition during specific procedural steps and anatomical knowledge were key points learned during the ASSET course. Such training may accelerate acquisition of specific trauma surgery skills to compensate for shortened training hours, infrequent exposure to major vascular injuries, or when just-in-time training is necessary. IPS is a benchmark for competence in extremity vascular control.

Diagnosis and evaluation of skeletal Class III patients with facial asymmetry for orthognathic surgery using three-dimensional computed tomography

Patients with facial asymmetry, especially skeletal Class III, have skeletal asymmetry in the cranial base, maxilla, mandible as well as asymmetry of soft tissues including the masticatory muscles. Three-dimensional (3D) computed tomography is considered as an effective tool to analyze these patients, since it enables accurate measurement without distortion regardless of head orientation using real anatomic surface landmarks and 3D representation of complex morphology including volumetric measurements. In this article, morphologic characteristics of the cranial base, mandible, and masticatory muscle in skeletal Class III patients with facial asymmetry are addressed, and 3D analysis for these patients is suggested. Furthermore, 3D evaluation of hard- and soft-tissue changes after orthognathic surgery is discussed, which can contribute to treatment planning for predictable treatment results.

Multimodal image-guided prostate fusion biopsy based on automatic deformable registration.

Transrectal ultrasound (TRUS)-guided random prostate biopsy is, in spite of its low sensitivity, the gold standard for the diagnosis of prostate cancer. The recent advent of PET imaging using a novel dedicated radiotracer, [Formula: see text]-labeled prostate-specific membrane antigen (PSMA), combined with MRI provides improved pre-interventional identification of suspicious areas. This work proposes a multimodal fusion image-guided biopsy framework that combines PET-MRI images with TRUS, using automatic segmentation and registration, and offering real-time guidance. The prostate TRUS images are automatically segmented with a Hough transform-based random forest approach. The registration is based on the Coherent Point Drift algorithm to align surfaces elastically and to propagate the deformation field calculated from thin-plate splines to the whole gland. The method, which has minimal requirements and temporal overhead in the existing clinical workflow, is evaluated in terms of surface distance and landmark registration error with respect to the clinical ground truth. Evaluations on agar-gelatin phantoms and clinical data of 13 patients confirm the validity of this approach. The system is able to successfully map suspicious regions from PET/MRI to the interventional TRUS image.

The umbilicus: a reliable surface landmark for the aortic bifurcation?

Anatomical surface landmarks are frequently used by clinicians to guide both diagnosis and treatment. Few studies have examined the reliability of vascular anatomical landmarks in living subjects. The umbilicus has traditionally been described as a surface landmark for the bifurcation of the abdominal aorta. This study examined the factors affecting the position of the umbilicus relative to that of the aortic bifurcation in 95 patients. 106 consecutive abdominal CT scans were analysed by a surgeon and radiologist. Following exclusion of CT scans with relevant significant intra-abdominal pathology, 95 patients were included in the study. Measurements were taken of the craniocaudal distance between the aortic bifurcation and umbilicus, as well as maximum subcutaneous fat thickness at the level of the umbilicus. Patient age and gender were also documented. The umbilicus was found to lie -6.3 ± 26.5 mm from the aortic bifurcation. Increasing subcutaneous fat thickness was associated with a more caudal position of the umbilicus relative to the aortic bifurcation. This result was highly statistically significant in males over 65 years old. This study suggests that the umbilicus is a reliable clinical surface landmark for the bifurcation of the abdominal aorta. Whilst some variation in craniocaudal distance exists between patients, in the majority of cases, the bifurcation of the abdominal aorta lies within a clinically narrow range of distances from the umbilicus.

Ultrasound-guided peripheral nerve blocks of the upper limb

Access the CPD MCQs for this issue online here ### Key points Compared with systemic analgesia, regional anaesthesia provides improved postoperative analgesia, reduced pain intensity, less postoperative nausea and vomiting (PONV), and increased patient satisfaction.1 The introduction of ultrasound guidance has been a marked advance in the practice of regional anaesthesia. This article will focus on ultrasound-guided (USG) peripheral nerve blocks (PNBs) of the upper limb. Traditionally, PNB has been reliant on surface landmark-based (LB) techniques aided by fascial clicks, loss of resistance, and neurostimulation for peripheral nerves with a motor component. Consequently, LB techniques of PNB in the upper limb have been restricted to sites at the elbow and wrist where surface landmarks are readily identified.2 Injection at these levels has the potential for neurological and vascular injury. Using ultrasound guidance the practitioner is no longer limited to the elbow and wrist. Peripheral nerves can be identified and traced to alternative sites where local anaesthetic (LA) can be safely injected without the risk of neurovascular injury. Variations in upper limb anatomy are commonly identified by ultrasonography and may, in part, explain the documented high incidence of block failure using traditional methods. USG selective PNB can also limit the extent of motor block or avoid it entirely by targeting sensory …

Morphology and Location of Surface Landmarks of Foramen Ovale in Kenyans

El foramen oval es una abertura quirurgicamente importante del craneo, que permite el enfoque y manipulacion del ganglio trigeminal ya que se encuentra en la impresion trigeminal (fosita de Meckel). Este enfoque transfacial, el enfoque de Hartel, requiere dos puntos anatomicos para la canalizacion precisa; el punto cigomatico y el punto de la pupila. Este estudio describe la morfologia y la ubicacion del foramen oval, y el punto pupilar en relacion al canto medial en la poblacion de Kenia. La junta directiva del Departamento de Anatomia Humana aprobo el estudio. Doscientos craneos secos procedentes del Departamento de Anatomia Humana se estudiaron utilizando un caliper digital con ayuda de un marco de medicion. Los resultados fueron analizados mediante el programa SPSS version 20. Los resultados mostraron que la longitud y ancho del foramen oval derecho fue de 7,69 mm media (±1,31) y 4,24 mm (±0,64), respectivamente, mientras que el foramen oval izquierdoo fue de 7,68 mm (±1,23) y 4,28 mm (±0,74). La distancia del punto cigomatico desde el meato acustico externo derecho fue 23,54 mm (±2,26) y el izquierdo de 23,49 mm (±2,16). Las distancias promedios del punto de la pupila en relacion con el canto medial fueron de 9,5 mm (el derecha) y 8,1 mm (el izquierdo). Estos resultados fueron significativamente diferentes de otros datos demograficos. El apoyo para la neuronavegacion para acceder al foramen oval en kenianos debe tener esto en consideracion.

A reappraisal of adult thoracic and abdominal surface anatomy via CT scan in Chinese population.

Accurate surface anatomy is essential for safe clinical practice. There are numerous inconsistencies in clinically important surface markings among and within contemporary anatomical reference texts. The aim of this study was to investigate key thoracic and abdominal surface anatomy landmarks in living Chinese adults using computed tomography (CT). A total of 100 thoracic and 100 abdominal CT scans were examined. Our results indicated that the following key surface landmarks differed from current commonly-accepted descriptions: the positions of the tracheal bifurcation, azygos vein termination, and pulmonary trunk bifurcation (all below the plane of the sternal angle at vertebral level T5-T6 in most individuals); the superior vena cava formation and junction with the right atrium (most often behind the 1st and 4th intercostal spaces, respectively); and the level at which the inferior vena cava and esophagus traverse the diaphragm (T10 and T11, respectively). The renal arteries were most commonly at L1; the midpoint of the renal hila was most frequently at L2; the 11th rib was posterior to the left kidney in only 29% of scans; and the spleen was most frequently located between the 10th and 12th ribs. A number of significant sex- and age-related differences were noted. The Chinese population was also compared with western populations on the basis of published reports. Reappraisal of surface anatomy using modern imaging tools in vivo will provide both quantitative and qualitative evidence to facilitate the clinical application of these key surface landmarks.

Manson's point: A facial landmark to identify the facial artery

The anatomy of the facial artery, its tortuosity, and branch patterns are well documented. To date, a reliable method of identifying the facial artery, based on surface landmarks, has not been described. The purpose of this study is to characterize the relationship of the facial artery with several facial topographic landmarks, and to identify a location where the facial artery could predictably be identified. Following institutional review board approval, 20 hemifacial dissections on 10 cadaveric heads were performed. Distances from the facial artery to the oral commissure, mandibular angle, lateral canthus, and Manson's point were measured. Distances were measured and confirmed clinically using Doppler examination in 20 hemifaces of 10 healthy volunteers. Manson's point identifies the facial artery with 100% accuracy and precision, within a 3 mm radius in both cadaveric specimens and living human subjects. Cadaveric measurements demonstrated that the facial artery is located 19 mm ± 5.5 from the oral commissure, 31 mm ± 6.8 from the mandibular angle, 92 mm ± 8.0 from the lateral canthus. Doppler examination on healthy volunteers (5 male, 5 female) demonstrated measurements of 18 mm ± 4.0, 50 mm ± 6.4, and 79 mm ± 8.2, respectively. The identification of the facial artery is critical for the craniofacial surgeon in order to avoid inadvertent injury, plan for local flaps, and in preparation of a recipient vessel for free tissue microvascular reconstruction. Manson's point can aid the surgeon in consistently indentifying the facial artery.

Normalizing Foot Moment Arm Lengths in Men and Women

Foot anthropometric dimensions may influence moment arm lengths and respective moments of force resisted by skeletal muscles. Depending upon circumstances, absolute or normalized expressions of these measures may have greater utility. PURPOSE: To determine the stability reliability and precision of two absolute and normalized moment arm lengths of the foot. METHODS: Longitudinal foot dimensions were obtained in 27 men and 27 women including the anterior-posterior distance between the posterior calcaneus and: 1) talocrural (TALO) and 2) metatarsophalangeal (META) joints. Bilateral measurements of seated subjects were performed using a digital sliding caliper. Absolute dimensions were normalized to height and lower-limb length (LLL, greater trochanter to lateral malleolus). Measures were obtained twice, separated by either 24 or 48 hours. Stability reliability was determined using intraclass correlation coefficient (ICC), and precision using standard error of measurement (SEM). RESULTS: The scatter of points around the trend lines for all 54 subjects combined appear to be uniform and the separate SEMs for men and women are similar. Assuming homoscedasticity, data are reported for the combined groups. For the 3 bilateral expressions of the 2 foot dimensions (12 measures), the low and high means (standard deviation) are reported for each session as well as the ICC and SEM for the pair of sessions. For TALO, means were 5.1 (0.4) and 5.2 (0.5) cm, ICCs were 0.79 and 0.82, and SEMs were 0.2 and 0.2. When normalized to height, means were 0.030 (0.002) and 0.030 (0.002) cm/cm height, ICCs were 0.65 and 0.75, and SEMs were 0.001 and 0.001. When normalized to LLL, means were 0.062 (0.005) and 0.063 (0.005) cm/cm LLL, ICCs were 0.69 and 0.73, and SEMs were 0.003 and 0.003. For META, means were 17.0 (1.2) and 17.1 (1.1) cm, ICCs were 0.97 and 0.98, and SEMs were 0.2 and 0.2. When normalized to height, means were 0.098 (0.002) and 0.100 (0.002) cm/cm height, ICCs were 0.92 and 0.94, and SEMs were 0.001 and 0.001. When normalized to LLL, means were 0.205 (0.010) and 0.208 (0.011) cm/cm LLL, ICCs were 0.92 and 0.92, and SEMs were 0.003 and 0.003. CONCLUSIONS: Surface landmarks and digital calipers can be used to precisely measure the 2 foot dimensions in question, whether or not they are normalized. Reliability is high for the META dimension, and lower for the TALO dimension. Meticulous data acquisition protocols are required to acquire potentially useful data.

Parametric body shape model of standing children aged 3–11 years

A statistical body shape model (SBSM) for children was developed for generating a child body shape with desired anthropometric parameters. A standardised template mesh was fit to whole-body laser scan data from 137 children aged 3–11 years. The mesh coordinates along with a set of surface landmarks and 27 manually measured anthropometric variables were analysed using principal component (PC) analysis. PC scores were associated with anthropometric predictors such as stature, body mass index (BMI) and ratio of erect sitting height to stature (SHS) using a regression model. When the original scan data were compared with the predictions of the SBSM using each subject's stature, BMI and SHS, the mean absolute error was 10.4 ± 5.8 mm, and 95th percentile error was 24.0 ± 18.5 mm. The model, publicly available online, will have utility for a wide range of applications.Practitioner Summary: A statistical body shape model for children helps to account for inter-individual variability in body shapes as well as anthropometric dimensions. This parametric modelling approach is useful for reliable prediction of the body shape of a specific child with a few given predictors such as stature, body mass index and age.

Comparison of Surface Landmarks for Measuring the Individualized Height of Rolling Walker

ABSTRACTAim: The purpose of this study was to determine whether the wrist joint crease (WJC) and femoral greater trochanter (FGT) methods differ in measuring a rolling walker (RW) height and recommended elbow flexion degree (EFD) and which one is more reliable and valid. Method: Twenty-eight older adults without postural deformity were measured using both methods initially and 5–7 days later. Results: Significant differences (all p < .01) between the WJC and FGT methods were identified on both RW height and the EFD. For the reliability comparison, the correlation coefficients for RW height and EFD from the WJC method were .962, and .596, respectively; while those from the FGT method were .769, and .360, respectively. The WJC method showed validity by generating elbow flexion within the recommended range but the FGT method did not. Conclusion: The WJC is more reliable and valid in measuring RW height and the recommended EFD than the FGT method.

Anatomy in the performance of a lower extremity fasciotomy before and after training

With shorter training hours, acquiring trauma surgical skills on-the-job is challenging for civilian and military surgeons. We hypothesize that a training course including lower extremity fasciotomy will improve knowledge of surgical landmarks, anatomical structures, and procedure time. Specifically, improved knowledge of surface landmarks will correlate with faster and successful 4 compartment decompression. Surgical residents (n=34) were tested with validated metrics performing a 2 incision 4 compartment fasciotomy on a cadaver before and after the Advanced Surgical Skills for Exposure in Trauma (ASSET) course. Surface landmarks, incision placement, surgical procedure steps, and procedure time were compared before and after training with Linear mixed models and Pearson correlation. After training, residents improved in landmark identification (+33%), incision placement (+34%), and successful 4 compartment decompression (p<0.001). More compartments were completely opened in less time (ANCOVA p<0.05; fig). Correct landmarks and incisions correlated with successful decompression (r=0.42-0.5; p<0.001). Improved surface anatomic knowledge increased successful fasciotomy. This knowledge is normally acquired on the job during residency but specific training may help accelerate the acquisition of fasciotomy skills to compensate for reduced training hours.

Human Temporal Bone Removal: The Skull Base Block Method.

Objectives To describe a technique for harvesting larger temporal bone specimens from human cadavers for the training of otolaryngology residents and fellows on the various approaches to the lateral and posterolateral skull base. Design Human cadaveric anatomical study. The calvarium was excised 6 cm above the superior aspect of the ear canal. The brain and cerebellum were carefully removed, and the cranial nerves were cut sharply. Two bony cuts were performed, one in the midsagittal plane and the other in the coronal plane at the level of the optic foramen. Setting Medical school anatomy laboratory. Participants Human cadavers. Main Outcome Measures Anatomical contents of specimens and technical effort required. Results Larger temporal bone specimens containing portions of the parietal, occipital, and sphenoidal bones were consistently obtained using this technique of two bone cuts. All specimens were inspected and contained pertinent surface and skull base landmarks. Conclusions The skull base block method allows for larger temporal bone specimens using a two bone cut technique that is efficient and reproducible. These specimens have the necessary anatomical bony landmarks for studying the complexity, utility, and limitations of lateral and posterolateral approaches to the skull base, important for the education of otolaryngology residents and fellows.

Prospective study to develop surface landmarks for blind axillary vein puncture for permanent pacemaker and defibrillator lead implantation and compare it to available contrast venography guided technique

ObjectiveTo develop surface landmarks for blind axillary vein puncture for pacemaker lead implantation. Methods and resultsPatients for routine coronary angiography were counseled for participating in our study. 20 patients who gave consent were taken up for axillary venogram after proper positioning at the time of coronary angiogram. The venograms of these 20 patients, were reviewed and the landmarks were used to develop a blind axillary puncture technique. Success rate of 100% was achieved with surface landmark guided axillary vein puncture. The implantation time while using surface landmark guided axillary puncture was not significantly longer than when venography based approach was used. Another interesting observation made from the study was that increasing BMI had a positive correlation with the time taken for venous access, the fluoroscopic time and the volume of contrast used, all the associations being statistically significant. Thus, the surface landmark guided technique is more safe and expeditious in non obese patients and probably in pediatric patients as well. Moreover, the new surface landmark guided approach is a significant safety step in terms of reducing the unwanted and avoidable radiation exposure to the hands. ConclusionThe results of this study demonstrate that placement of endocardial permanent pacemaker and ICD leads via the developed surface landmarks is effective and safe and is devoid of the harmful effects of radiation and contrast exposure.

Commentary on: Rhinoplasty: The Nasal Bones - Anatomy and Analysis.

The authors undertake a cadaver study whose purpose is to provide increasingly precise anthropometric and clinical measurements to remove some of the ambiguities that currently exist in the medical literature.1 For example, the terms “nasion” and “sellion” are often confused. We have been guilty ourselves of referring to the nasion as the deepest point of the concavity of the cephalic end of the nasal bone where it merges into the glabella. In fact, the sellion is the deepest point of that concavity. The authors carefully define their terms and proceed to perform detailed measurements of the bony structure of the nose. They remove ambiguities whenever possible. For example, they remind us not to confuse surface (skin) landmarks with …

Surface landmark of the facial vein for the dermal fillers injection

ObjectiveThe purpose of this study was to describe the course of the facial vein and identification of surface landmark of the facial vein for dermal fillers injections. MethodsThirty flaps of hemiface were turned over to measure the distance between the facial vein and ala of the nose and oral commissure. The vertical distance was measured from the inferior orbital rim to the facial vein. The diameter of the facial vein and the depth from skin surface to the facial vein were measured. Anatomical relationships of the facial vein to its surrounding structure were observed. ResultsThe course of the facial vein is a large curved course without tortious from the medial canthal tendon downward along the medial orbital rim. The mean vertical distance from the facial vein to the inferior orbital rim was 6.87±1.14mm. The average horizontal distance from the facial vein to ala of nose was 21.57±3.95mm. The average horizontal distance from the facial vein to oral commissure was 27.55±3.97mm. The average depth values from skin surface to the facial vein at the level of ala of nose and oral commissure were 14.44±2.90 and 15.38±2.40mm, respectively. ConclusionsThe course of the facial vein at the level of ala of nose and the oral commissure were approximately 2 and 3cm, respectively at the depth of 1.5cm.

Age- and gender-related changes in pediatric thoracic vertebral morphology

Background contextAlthough it is well known that the growth of thoracic spine changes significantly with age, gender, and vertebral level in the skeletally normal pediatric population, there have been very few studies attempting to comprehensively quantify such variations. Biomechanical and computational models of the growing thoracic spine have provided insight into safety and efficacy of surgical and noninvasive treatments for spinal deformity. However, many of these models only consider growth of the vertebral body and pedicles and assume a consistent growth rate for these structures across thoracic levels. PurposeTo enhance the understanding of age-, gender-, and level-related growth dynamics of the pediatric thoracic spine by comprehensively quantifying the thoracic vertebral morphology for subjects between 1 and 19 years. Study designA retrospective computed tomography (CT) image analysis study. MethodsRetrospectively obtained chest CT scans from 100 skeletally normal pediatric subjects (45 males and 55 females between the ages 1 and 19 years) were digitally reconstructed using medical imaging software. Surface point clouds of thoracic vertebrae were extracted and 26 vertebral geometry parameters were measured using 25 semiautomatically identified surface landmarks and anatomical slices from each thoracic vertebra (T1–T12). Data were assessed for normality, symmetry, and age-, gender-, and level-related differences in geometric measures and growth. Linear regression was performed to estimate of the rates of variation with age for each measurement. ResultsAsymmetries (bilateral, superior-inferior, and anteroposterior) were observed in vertebral body heights, end plate widths and depths, and interfacet widths. Within genders, significant interlevel differences were observed for all geometric measures, and significant differences in the rates of growth were found across thoracic levels for most parameters. Significant differences were observed between genders for pedicle, spinous process, and facet measurements. Growth rates of the pedicles and vertebral bodies were also found to vary significantly between genders. ConclusionsThe rates of growth for most thoracic vertebral structures varied between genders and across vertebral levels. These growth rates followed trends similar to those of their associated vertebral dimensions and this indicates that, across levels and between genders, larger vertebral structures grow at faster rates, whereas smaller structures grow at a slower rate. Such level- and gender-specific information could be used to inform clinical decisions about spinal deformity treatment and adapted for use in biomechanical and computational modeling of thoracic growth and growth modulation.